com.mayabot.nlp.algorithm.collection.bintrie.TrieTreeForwardMaxMatcher Maven / Gradle / Ivy
/*
* Copyright 2018 mayabot.com authors. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.mayabot.nlp.algorithm.collection.bintrie;
import java.util.List;
/**
* 算法改造来自Ansj开源的分词项目。
* 匹配器，可以扫描一次文本，获得词典中的最大前向匹配或者全匹配。
*
* @param
* @author jimichan
* @author ansj
*/
public class TrieTreeForwardMaxMatcher implements TrieTreeMatcher {
private static final String EMPTY_STRING = "";
private final BinTrieTree tree;
private int offset;
private int root = 0;
private int i = this.root;
private boolean isBack = false;
private BinTrieNode branch;
private String text;
private String str;
private int tempOffset;
private final int len;
private T param;
TrieTreeForwardMaxMatcher(BinTrieTree tree, String content) {
this.text = content;
this.tree = tree;
this.branch = tree;
this.len = content.length();
}
/**
* 前向最大長度匹配
*
* @return String
*/
@Override
public String next() {
String temp = this.frontWordNext();
while (EMPTY_STRING.equals(temp)) {
temp = this.frontWordNext();
}
return temp;
}
private String frontWordNext() {
for (int up = len + 1; this.i < up; this.i++) {
if (i == len) {
this.branch = null;
} else {
this.branch = this.branch.findChild(this.text.charAt(this.i));
}
if (this.branch == null) {
this.branch = this.tree;
if (this.isBack) {
this.offset = this.root;
this.str = this.text.substring(this.root, this.root + this.tempOffset);
//this.str = new String(this.chars, this.root, this.tempOffset);
if ((this.root > 0) && (isE(this.text.charAt(this.root - 1))) && (isE(this.str.charAt(0)))) {
this.str = EMPTY_STRING;
}
if ((this.str.length() != 0) && (this.root + this.tempOffset < this.text.length()) && (isE(this.str.charAt(this.str.length() - 1)))
&& (isE(this.text.charAt(this.root + this.tempOffset)))) {
this.str = EMPTY_STRING;
}
if (this.str.length() == 0) {
this.root += 1;
this.i = this.root;
} else {
this.i = (this.root + this.tempOffset);
this.root = this.i;
}
this.isBack = false;
if (EMPTY_STRING.equals(this.str)) {
return EMPTY_STRING;
}
return this.str;
}
this.i = this.root;
this.root += 1;
} else {
switch (this.branch.getStatus()) {
case AbstractTrieNode.Status_Continue:
this.isBack = true;
this.tempOffset = (this.i - this.root + 1);
this.param = this.branch.getValue();
break;
case AbstractTrieNode.Status_End:
this.offset = this.root;
//this.str = new String(this.chars, this.root, this.i - this.root + 1);
this.str = this.text.substring(this.root, this.i + 1);
String temp = this.str;
if ((this.root > 0) && (isE(this.text.charAt(this.root - 1))) && (isE(this.str.charAt(0)))) {
this.str = EMPTY_STRING;
}
if ((this.str.length() != 0) && (this.i + 1 < this.text.length()) && (isE(this.str.charAt(this.str.length() - 1)))
&& (isE(this.text.charAt(this.i + 1)))) {
this.str = EMPTY_STRING;
}
this.param = this.branch.getValue();
this.branch = this.tree;
this.isBack = false;
if (temp.length() > 0) {
this.i += 1;
this.root = this.i;
} else {
this.i = (this.root + 1);
}
if (EMPTY_STRING.equals(this.str)) {
return EMPTY_STRING;
}
return this.str;
}
}
}
this.tempOffset += len;
return null;
}
private boolean isE(char c) {
return c == '.' || ((c >= 'a') && (c <= 'z'));
}
// public void reset(String content) {
// this.offset = 0;
// this.root = 0;
// this.i = this.root;
// this.isBack = false;
// this.tempOffset = 0;
// this.text = content;
// this.branch = this.tree;
// }
/**
* 当参数对象是列表或者数组的时候，返回指定下标的内容。否则返回null
*
* @param i
* @return String
*/
@Override
public String getParam(int i) {
if (param != null) {
if (param instanceof String[]) {
String[] _p = (String[]) param;
if (_p.length > i) {
return _p[i];
}
} else if (param instanceof List) {
List list = (List) param;
return list.get(i).toString();
}
}
return null;
}
/**
* 得到全部参数
*
* @return String
*/
@Override
public T getParams() {
return this.param;
}
@Override
public int getOffset() {
return offset;
}
}